Reproducing apparatus having an optical head system

ABSTRACT

A reproducing apparatus for reproducing an information signal from a recording medium in which a recording medium has a modulated information signal recorded thereon by one of different recording systems, includes an optical head for irradiating the recording medium with a light beam, a photoelectric detecting portion for receiving a light beam reflexed from the recording medium and for generating an electric signal as the modulated information signal in response to the received light beam, and a convertor for converting the information signal from the electric signal. The photoelectric detecting portion is arranged to generate the electric signal by different processes in the case where the modulated information signal is recorded on the recording medium by a first system and in the case where the modulated information signal is recorded on the recording medium by a second system different from the first system. The convertor includes a demodulation circuit which is commonly utilized for demodulating both modulated information signals recorded by the first and second systems.

This application is a division of application Ser. No. 07/993,134, filedDec. 18, 1992, which is a division of Ser. No. 07/863,527, filed Apr. 3,1992, abandoned, which is a continuation of Ser. No. 07/702,108, filedMay 15, 1991, abandoned, which is a division of Ser. No. 07/235,904,filed Aug. 24, 1988, abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to record bearing media and, more particularly,to recording media on which still pictures and time-serial informationrelevant to the still pictures are to be recorded.

2. Description of the Related Art

At present, in case of preserving the record of scenes not only in thedaily living but also at memorial functions, etc. in the form of images,there are occasions of using VTRs for motion pictures and accompanyingsounds and still video recorders and silver halide cameras for stillpictures.

Also, of the conventional record bearing media there are video discssuch as laser disc and VHD. With such media, motion picture informationof 30 minutes to a few hours is recorded in only one item. Inapplication to, for example, still pictures, for the NTSC system ofabout 1,800 frames a minute, or for the high-definition television ofabout 360 frames a minute, it is, therefore, possible to store as manystill pictures as ten thousand to two hundred thousand in one item ofthe recording medium. There is another system called "AHD" wherein thestill image before to be recorded in the disc-shaped medium is changedto digital code.

In the prior known information recording media of the type describedabove, an enormous volume of data could be recorded in one item of therecording medium. On its reverse side, however, this enormous volume ofdata had its arrangement made complicated, giving rise to a number ofproblems that it was difficult to swiftly reproduce an actuallynecessary small amount of information, that the information was hardlycontrolled, and that the size was too large to carry aroundconveniently.

Also, to handle the signals including the dimension of time such asvideo signals for motion picture, the accompanying audio signals andother time-serial signals together with signals having no time factor orthe still image information, great difficulty arose with theconventional recording medium.

Also, situations in which the record has to be rewritten to suit tospecial purpose, or permanent preservation is necessary, problems areencountered. It is, therefore, desired to develop a medium for stillimage files which can cope with a wide variety of purposes as such.

The video discs that have so far been used were obtained by manyrecording methods. As to the reproducing means too, various reproductioncapabilities suited to them have been considered.

As such a medium is in either of the forms that is possible to rewriteand that is impossible to rewrite, it is also generally desirable toselectively use both of them depending on the given situation.

On the contrary, because the conventional reproduction apparatus differwith different recording methods as has been described above, for theoptical discs of different recording methods are reproduced, thereproduction apparatus adapted to the recording methods must be set upon all such occasions. However, the conventional reproduction apparatusare out of compatibility. Hence there was a problem that depending onthe sort of record bearing medium used, a choice among the differentreproduction apparatus had to be made.

Also, to deal with the picture on the record bearing medium, thetreatment differs largely between the video signal as was recordedoriginal and the once or more copied one. Therefore, it is desired thatif the given record bearing medium is not original, then the number ofgenerations the copy is of, becomes possible to determine.

SUMMARY OF THE INVENTION

An object of the present invention is to eliminate the above-describedproblems.

Another object is to provide a record bearing medium capable of dealingthe still picture information and the time-serial information both in agood efficiency.

Under such an object, in an embodiment of the invention, a sheet-shapedrecord bearing medium is proposed, comprising a first recording area inwhich a fixed amount of information is always recorded, the firstrecording area having a still image signal recorded therein, and asecond recording area in which an amount of recorded information is notconstant, the second recording area having a time-sequential signalrecorded therein.

Still another object of the invention is to provide a record bearingmedium suited to set up various systems which are relevant to stillpictures.

Under such an object, in an embodiment of the invention, a sheet-shapedrecord bearing medium is proposed, comprising a first recording area inwhich a fixed amount of information is always recorded, the firstrecording area having a still image signal recorded therein, and asecond recording area in which an amount of recorded information is notconstant, the second recording area having recorded therein atime-sequential control signal for time-sequentially controlling anapparatus connected to a reproduction apparatus for reproduction fromthe record bearing medium.

A further object of the invention is to provide a record bearing mediumof which the handling method the user can readily understand.

Under such an object, in an embodiment of the invention, a sheet-shapedrecord bearing medium is proposed, comprising a first recording area inwhich a fixed amount of information is always recorded, the firstrecording area having recorded therein a still image signal and datarepresenting the number of copy generations of the record bearingmedium, and a second recording area in which an amount of recordedinformation is not constant, the second recording area having atime-sequential signal recorded therein.

Other objects of the invention than those described above and itsfeatures will become apparent from the following detailed description ofembodiments thereof by reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of the recording surface of an embodiment of arecord bearing medium according to the invention.

FIG. 2 is a diagram illustrating an example of construction of arecording and reproduction system using the record bearing medium ofFIG. 1.

FIG. 3 is a plan view looked from one side of another embodiment of therecord Bearing medium according to the invention.

FIG. 4 is a sectional view of the record bearing medium of FIG. 3.

FIG. 5 is a diagram illustrating an example of construction of arecording and reproduction system using the record bearing medium ofFIGS. 3 and 4.

FIG. 6 is a block diagram of an example of construction of the signalprocessing circuit in the printer of FIG. 5.

FIG. 7 is a diagram of another example of construction of the recordingand reproduction system using the record bearing medium of FIG. 3.

FIGS. 8(a), 8(b) and 8(c) are diagrams to explain the recording methodusing the magneto-optical effect.

FIGS. 9(a), 9(b) and 9(c) are diagrams to explain the method ofreproducing the record bearing medium by using the magneto-opticaleffect.

FIG. 10 is diagrams to explain a process for recording by changingphysics with the use of light.

FIG. 11 is diagrams to explain a process for recording by changing thereflectivity on the record bearing medium.

FIG. 12 is a block diagram illustrating a copy system using the recordbearing medium according to the invention.

FIG. 13 is a diagram roughly illustrating the structure of a controlsystem using the record bearing medium according to the invention.

FIGS. 14(a) and 14(b) are plan views illustrating respectively practicalexamples of the record bearing medium usable in the system of FIG. 13.

FIG. 15 is a diagram illustrating the construction and arrangement ofthe main parts of the recording and reproduction apparatus in FIG. 13.

FIG. 16 is a perspective view illustrating the details of the stopper inFIG. 15.

FIGS. 17(a) and 17(b) are a block diagram illustrating a practicalarrangement of the parts of the signal processing circuit of FIG. 15.

FIG. 18 is a plan view illustrating the arrangement of picture elementsfor a still picture signal to be recorded on the record bearing mediumof FIG. 14(a).

FIG. 19 is a diagram illustrating a record format for MIDI signals andaudio signals to be recorded on the record bearing medium of FIG. 14(a).

FIG. 20 is a diagram illustrating an example of application of thecontrol system of FIG. 13.

FIG. 21 is a diagram illustrating another example of application of thecontrol system of FIG. 13.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the back side (recording surface) of an optical disc forrecording motion picture--still pictures, which constitutes oneembodiment of the invention. In FIG. 1, 1 is a protection layer; 2 is afirst area in which a fixed quantity of information is always recorded,or that area which records still pictures. 3 is a second area in whichthe record information quantity is variable, or that area which recordsinformation other than the still pictures, for example, motion pictures.4 is a recessed portion for indicating the center of the disc andfixedly securing the disc when the disc rotates by a driver device. 5are projections for fixing the disc at the time of rotation. 6 is therecording surface on the back side of the disc.

Also, FIG. 2 is a block diagram illustrating a system for digitalrecording (picture recording, sound recording) and reproduction usingthe disc shown in FIG. 1. The system comprises a camera 15 forgenerating motion picture signals to be recorded in the second area, ananalog-to-digital (A/D) converter 16, a band compression circuit 17 forcompressing the information quantity, a microphone 18 for inputting thesound the motion picture accompanies, an A/D converter 19 which is forsound, an audio signal processing circuit 20 for treating digital audiodata, a coupler 21 for coupling the motion picture and accompanyingsound to form signals of one system, a redundancy adding circuit 22 forcorrecting error, a camera 23 which generates still picture signals tobe recorded in the first area, an A/D converter 24 which is for thestill picture signals, a redundancy adding circuit 25 for correctingerror, a selection circuit 26 for producing one of the still picture andthe motion picture that is the information other than the still picture,a code modulation circuit 27 for digital modulation, a photomagneticmodulator 28 using the magneto-optical effect for recording digitalsignals on a photomagnetic disc 29, a photomagnetic demodulator 30 usingthe magneto-optical effect, a code demodulator 31 for demodulating thedigital data, a selection circuit 32 for outputting the still pictureand the motion picture in differentiation, an allotter 33 for separatingthe video signal and the audio signal, a band expansion circuit 34 forexpanding the data amount of the recorded digital data, adigital-to-analog (D/A) converter 35 for converting the digital data tothe analog data, a display 36 such as CRT for projecting a motionpicture, an audio signal processing circuit 37 for the audio dataseparated by the allotter 33, a D/A converter 38 for converting thedigital audio data to the analog form, a speaker 39 for producing sound,and a signal processing circuit 40.

In FIG. 2, the motion picture camera 15 when shooting produces videodata or analog data which are then converted to digital data of themotion picture by using the A/D converter 16. And, using the bandcompression circuit 17, the digital data of that motion picture iscompressed. Also, when shooting the camera 15, the accompanying sound(other sounds such as background music (B.G.M.) will do good) enters themicrophone 18. Its audio signals, or analog data, are converted to audiodigital data by using the A/D converter 19. And, its audio digital dataafter having been digitally treated in the signal processing circuit 20are coupled with the motion picture digital data produced from the bandcompression circuit 17 by the time division multiplex or like method inthe coupler 21. In the redundancy adding circuit 22, a redundancy codefor error correction is then added. Next, a video signal as the stillpicture shot by the still picture camera 23 is made to be a digital dataof the still picture by the A/D converter 24. And, in the redundancyadding circuit 25, a redundancy code for error correction is added.Next, the switch of the selection circuit 26 is thrown to a terminal "b"side so that the digital data comprising the motion picture and soundfrom the circuit 22 are code-modulated by using the code modulationcircuit 27. And, the motion picture, sound digital data are recordedthrough the photomagnetic modulator 28 using the magneto-optical effectto the motion picture recording area 3 of FIG. 1. Also, the switch ofthe selection circuit 26 is thrown to a terminal "b" side so that thestill picture digital data that are the output of the redundancy addingcircuit 25 are recorded, similarly to the motion picture sound digitaldata, through the code modulation circuit 27 and the photomagneticmodulator 28 to the still picture recording area 2 (FIG. 1) on thephotomagnetic disc 29. Thus, the still picture, the motion picture andthe sound are digitally recorded on one item of disc.

Next, reproduction is described. At first, in the photomagneticdemodulator 30 using the magneto-optical effect, the motion picture,still picture, sound data on the photomagnetic disc 29 are read. Then,the modulated digital data is demodulated by the code demodulationcircuit 31 to the original signals. And, with the switch of theselection circuit 32 thrown to a terminal "a'" side, the motion picture,sound digital data are caused to enter the allotter 33 wherein the sounddigital data and the motion picture digital data are separated. Then,the data of the motion picture enters the band expansion circuit 34,wherein the digital data is expanded. Then, the expanded data isconverted to analog data by the D/A converter 35 and output as themotion picture in the CRT of the display 36.

Also, the sound digital data output from the allotter 33 is suppliedthrough the audio signal processing circuit 37 to the D/A converter 38,and is output as the analog data or sound from the speaker 39 in thesynchronized form with the motion picture produced from the CRT of thedisplay 36. Next, with the switch of the selection circuit 32 thrown toa terminal "b'" side, the still picture digital data is caused to enterthe signal processing circuit 40 to be output to the CRT of the display36'.

By the foregoing operation, the digital data comprising the motionpicture, still picture and sound on the photomagnetic disc is output tothe CRT, printer and speaker.

It should be noted that, in the above-described system, the motionpicture and the still picture have been input from the different sourcesfrom each other by using the respective individual cameras, but if themotion picture camera is improved in the image pickup power and madeable to record one frame of picture by a frame memory, one scene of themotion picture can be recorded as a still picture by using such a motionpicture camera.

The above-described information recording medium can record stillpictures and other classes of information other than that of stillpictures in one item of disc, so that there is a merit that the abilityto search from one class to another is excellent and the control ofinformation is easy to perform.

Next, a photomagnetic disc as another embodiment of the invention isdescribed. The back surface (recording surface) of the photomagneticdisc of this embodiment is the same as shown in FIG. 1. FIG. 3 is a viewillustrating the front surface (print surface) of the photomagnetic discof this embodiment. FIG. 4 is a sectional view of the photomagnetic discshown in FIG. 3. In FIGS. 3 and 4, 6 is a record bearing surface that isthe back surface of the disc; 7 is a print of still picture printed out;8 is a bar code for use in arrangement of the disc. As shown in FIG. 3,the bar code 8 is provided at the center of the lower margin or one ofthe corners of the print surface 9. 9 is the print surface that is thefront surface of the disc. 10 is a protection layer, 11 is a recordlayer, 12 is a print layer.

Also, FIG. 5 is a block diagram illustrating a system for recording(picture recording, sound recording), reproduction using the disc shownin FIGS. 1, 3, 4. In the figure, the similar parts to those of FIG. 2are denoted by the same numerals and their explanation is omitted.

In FIG. 5, 41 is a printer for printing out the processed digital stillpicture data in the signal processing circuit 40 on a sheet of paper, ora medium other than that directly by ink; 42 is a signal processingcircuit similar to the signal processing circuit 40; 43 is a printersimilar to the printer 41; 44 is a selection circuit for selectingwhether to print out or to present, as it is, the still picture at thedisplay 36'.

In the system of FIG. 5, similarly to the system of FIG. 2, the digitaldata comprising the motion picture, still picture, sound on thephotomagnetic disc is output to the CRT, printer, speaker. Also, inorder that what is recorded in this disc is quickly understandable, astill picture as the print 7 of FIG. 3 is affixed. For this purpose, thedata from the A/D converter 24 is digitally treated in the signalprocessing circuit 42, and printed out on paper in the printer 43. Asshown in FIG. 3, it is affixed to the front surface of the disc which isthe print surface 9. This print may be a picture obtained by printingout the still picture data input from the selection circuit 44 to theprinter 41.

FIG. 6 is a block diagram of a practical example of the circuitstructure for signal treatment in the interior of the printer 41 or 43in FIG. 5. 51, 52 and 53 are buffer memories; 54, 55 and 56 are reversegamma converting circuits for R signal, G signal, B signal respectively;57, 58 and 59 are density converting circuits for printer; 60 is a blackcolor detecting circuit; and 61 is a printer output signal processingcircuit.

The digital signals of R, G, B from the signal processing circuit 40 or42 are converted in the data rate by the buffer memories 51, 52 and 53.Next, in the reverse gamma converting circuits 54, 55 and 56, the gammacorrection applied signals are returned to the original signals (linearsignals). In the NTSC signal, on the transmitter side, the non-lineartreatment in conformance to the non-linear characteristics of thefluorescent surface, or the γ correction, is carried out. Therefore, thecorrection circuits of 1/γ or the reverse gamma converting circuits 54,55 and 56 become necessary. But, in the case that this γ correction iscarried out on the receiver side, the reverse gamma converting circuits54, 55 and 56 become unnecessary. And, by the density convertingcircuits 57, 58 and 59 for the printer the R, G, B signals of theadditive color process are converted to three primary colors C, M, Y ofthe subtractive color process having the reference of white color, anddensity correction is carried out to bring fourth gradation when toprint. Next, in the black (BL) detecting circuit 60, BL is formed fromthe three colors C, M, Y. And, in the signal processing circuit 61, thefour colors C, M, Y, BL are signal-processed appropriately to suit tothe printer, and its output is printed out.

The above-described information record bearing medium has the stillpicture and information other than the still picture recorded in onesheet of disc, and further has on its opposite surface a pictureconcerning the still picture. Therefore, there is a merit that theinformation is easy to control and to search.

FIG. 7 is a block diagram illustrating another arrangement of the systemusing the disc shown in FIGS. 1, 3 and 4. In the figure, the similarconstituent parts to those of FIG. 5 are denoted by the same numerals.

In FIG. 7, 116 is an amplifier for amplifying the analog video signalobtained from the camera 15; 118 is an amplifier for amplifying theanalog audio signal obtained from the microphone 17; 119 is a couplerfor coupling the motion picture signal and the audio signal to form asignal of one system; 121 is an amplifier for amplifying the analogstill picture signal obtained from the camera 23; 122 is a selectioncircuit for selecting one of the analog motion picture signal and thestill picture signal to produce at its output; 123 is a photomagneticmodulator using the magneto-optical effect for recording the signal onthe photomagnetic disc 29; 125 is a photomagnetic demodulator using themagneto-optical effect; 126 is a selection circuit for selectivelyproducing the analog still picture signal or the analog motion picturesignal; 127 is an allotter for separating the analog motion picturesignal and the analog audio signal; 128 and 130 are amplifiers foramplifying the analog motion picture signal and the audio signal; 132 isa signal processing circuit for the analog still picture signal; 133 isa selection circuit for selecting whether the-still picture signal isproduced to the display 36' or produced to the printer 134.

In the circuit of FIG. 7, the analog video signal produced by the motionpicture camera 15 is amplified by the amplifier 116, and the analogaudio signal from the microphone 17 is amplified by the amplifier 118.The signals from these amplifiers 116 and 118 are coupled by the timedivision multiplex or like method in the coupler 119. Next, the analogstill picture signal obtained by the camera 23 for still picture isamplified by the amplifier 121. And, the switch of the selection circuit122 is thrown to the terminal "a" side, so that the analog signalcomprising the motion picture and sound passes through the photomagneticmodulator 123 using the magneto-optical effect and is recorded in therecording area 3 of the photomagnetic disc of FIG. 1. Also, the switchof the selection circuit 122 is thrown to the terminal "b" side, so thatthe analog still picture signal that is the output from the amplifier121 passes through the photomagnetic modulator 123 and is recorded onthe still picture recording area 2 on the photomagnetic disc 29.

Next, reproduction is described. At first, each signal of the motionpicture, still picture and sound is obtained from the analog signal fromthe photomagnetic disc 29 by the photomagnetic demodulator 125 using themagneto-optical effect. And, on throwing the selection circuit 126 tothe terminal "a'" side, the motion picture and audio signals aresupplied to the allotter 127 wherein the audio signal and the motionpicture signal are separated. The motion picture signal passes throughthe amplifier 128 and is output as the motion picture to the CRT or likedisplay 36. Also, the audio signal produced from the allotter 127 passesthrough the amplifier 130 and is output as the sound from the speaker 39in the synchronized timing with the motion picture the display 36produces. Next, on setting the output of the selection circuit 126 tothe terminal "b'" side, the still picture signal is caused to enter thesignal processing circuit 132. Further by the selection circuit 133, itis input to the display 36' or the printer 134 for printout.

Also, for quick understanding of what is recorded in this photomagneticdisc, to affix the still picture as the print 7, it is treated by thesignal processing circuit 135, and printed out by the printer 136. Theprintout is affixed to the print surface 9 of the disc like that shownin FIG. 3. This print may be the one printed out from the printer 134.

Next, the process for performing recording on the photomagnetic disc byusing the magneto-optical effect is described by using FIGS. 8(a), 8(b)and 8(c). As the material of the disc, the disk is fabricated bysputtering TbFeCo, TbDyFeCo is widely used. In these ferromagneticmaterials, when the temperature is increased, the fluctuation of themagnetic moment of the atoms becomes strong, and the magnetizationlowers. By utilizing this phenomenon, the magnetization is inverted toeffect recording. For this, a weak magnetic field H is given in adirection desired to record as shown in FIG. 8(a). Then, as shown inFIG. 8(b), a laser beam is irradiated at where the operator wants towrite and the temperature of that place is increased. As a result, asshown in FIG. 8(c), the magnetization M of the record bearing medium isinverted by the magnetic field H. After the irradiation of the beam, therecording is fixed in the form of the difference in the direction ofmagnetization.

So, reproduction is carried out by reading this difference of thedirection of magnetization. In this reproduction, the magneto-opticaleffect is used. That is, the linearly polarized light (the light that isso polarized that the direction of the electric field vector is alwaysconstant) advances in the magnetic material, thereby rotating thepolarization plane. This phenomenon is called Faraday effect. The angleof rotation of this time is called Faraday rotation angle. Also, whenthe direction of magnetization is reversed, the polarization planerotates to the opposite direction. This phenomenon in terms of thereflected light is called Kerr effect. The angle of rotation of thistime is called Kerr rotation angle.

A case where the record bearing medium on which a signal has beenrecorded by using the magneto-optical effect is subject to apreproduction of the signal by using the above-described Kerr effect isdescribed by using FIGS. 9(a)-9(c).

A laser beam for reading is irradiated on the record bearing medium asshown in FIG. 9(a). Next, when the reflected laser beam is lookedthrough an analyzer as shown in FIGS. 9(b) and 9(c), the difference ofrotation between (+) (FIG. 9(b)) and (-) (FIG. 9(c)) appears as adifference in intensity of the light. Hence, the data can be reproducedby the two logic values of (+) and (-).

Next, a light recording method of forming the difference of theintensity of reflection in the recording medium is described. In thiscase, the material of the record bearing medium may be, for example, ofthe phase change type with crystal-amorphous structure of TeOx with Suand Ge additives, or of crystal-crystal structure of SeInSb, or of thesemiconductor-metal structure of VO₂ thin film. In the following, therecord bearing medium that has used the change of reflectivity of thetwo states of the crystal-amorphous phase change type.

The not yet recorded portion of the record bearing medium is in thecrystal state. When this is irradiated with the laser beam, as thetemperature of the irradiated portion increases, it melts. Then when theirradiation is stopped and rapid cooling is applied, it becomes anamorphous state. That portion which has become the amorphous state isthe recorded portion. The thus recorded recording medium is theamorphous state in the recorded portion and the crystal state in the notyet recorded portion. In the case that reproduction is applied to therecord bearing medium having these two states, a light beam forreproduction is irradiated to the record bearing medium, discriminationbetween the recorded and the not recorded is made by detecting thereflectivity to the irradiated light in the two states or the crystalstate and the amorphous state. The thing of this recording method is thething of the rewritable type. By returning this rewritable type recordbearing medium to the crystal state, the recorded portion is erased. So,a recorded portion of the amorphous state can be made up again bycarrying out the laser beam irradiation for writing.

Also, though similar to that described above in the point of reaction bythe heat of the laser beam, recording is effected physically orchemically by the difference of the film of the surface of material.These are called "WORM: write once read many" type.

As the thing of this WORM type, it can not always be the disc-shapedrecord bearing medium. One surface of a card of the same size as that ofthe publicly known credit card can be recorded by the method that aplurality of optical heads mounted on a rotary drum alternately recordon the card.

As this method of physically recording by the head of the laser beam,bits are provided by the head of the laser beam in the material of TeC,CS₂ -Te, Tb-Te-Se and TeTiAgSe, etc. to effect physical recording.

Also, as the method of chemically recording, there is a method ofrecording by chemically changing the reflectivity that is the propertyof the record bearing medium by the heat of the laser beam to a materialobtained by doping Ab, Au in TeO₂ to accelerate the speed of reaction,or materials of Bi₂ Te₃ -Sb₂ Se₃, etc.

As materials other than the Te system, there are materials of bubblemode such as InCH₄ O₂, moss eye mode, and other organic pigment systemmaterials, which are usable in the physical recording method.

In the following, As the method of recording by physical change such asformation of a difference of the film of the surface of material bylight, an example of TeC is described by reference to FIG. 10.

At first, as a part (a) of FIG. 10, a laser beam is irradiated to thefilm of the material surface. Then, by the head of this laser beam, itis heated to about 140° C. at which the alkyl molecule groups evaporate.As shown by a part (b) of FIG. 10, the Te fine particle groups remain,becoming crystalline. Further, when the irradiation of the laser beamcontinues, it melts at 440° C. and a bit is formed as shown in a part(c) of FIG. 10.

Next, as to the method of recording chemically, there are two chemicalrecording methods, one of which is to record by the amorphous-crystalphase change, and the other of which is-to record by alloy (changing thereflectivity).

The recording by the amorphous-crystal phase change uses TeOx (x=1.1 atoptimum) as the material of the recording medium. So, Te and TeO₂ arevacuum evaporated separately from the respective vacuum evaporationports. The film after the vacuum evaporation has a structure that Teparticles of about several tens of Å are uniformly dispersed in theamorphous or TeO₂ matrix. When the laser beam is irradiated to thismaterial, the amorphous melts and, when cooled, becomes crystal. And,while when in the amorphous the reflectivity for the laser beam was 20%,the crystal gains a reflectivity of 40%.

Next, the method of changing the reflectivity by making alloy isdescribed according to FIG. 11. The recording medium is constructed inthe structure of Bi₂ Te₃ of large light absorption coefficientsandwiched between two layers Sb₂ Se₃ of small light absorptioncoefficient with an Al layer at the top, totaling 4 layers, and thefront surface being coated with a protection film. When recording onthis 4-layer recording medium, the laser beam is irradiated to therecording medium. Thereby the heated Bi₂ Te₃ by the heat of the laserbeam diffuses into Sb₂ Se₃ lying in its upper and lower layers to makean alloy 70, thus carrying out the recording.

Since other physical recording methods using ones of the bubble modeusing InCH₄ O₂ as other than Te system, and other organic pigment systemmaterials, all are the publicly known techniques, their explanation isomitted.

It should be noted that when reading the record bearing medium recordedby a recording method using Kerr effect, the reading has to be madethrough the analyzer, but the others which are read by detecting thestrength of reflection does not necessitate the analyzer. Therefore, inthe case of a reproduction from the record bearing medium by using themagneto-optical effect, the laser beam for reading is detected throughthe analyzer, while when to read the other record bearing medium,detection is made not through the analyzer.

Since the record bearing media on which signals have been recorded byall the above-described methods, regardless of whether the informationrecorded is unable to rewrite or the information recorded is able torewrite, can be reproduced by the light signal corresponding to thestrength of reflection of the irradiation light, the structure of thesystem is simplified and they become applicable to various purposes.

FIG. 12 is a block diagram to explain a copy system for theabove-described record bearing medium. In the figure, 74 is a dynamicrandom access memory (D-RAM), and a data reproducer 73, a data recorder75 and a color printer 78 correspond to the respective constituentelements in the system of FIG. 5. The first recording area 2 of therecord bearing medium to be used in this copy system is provided with anID region in which an index signal representing the number of timescounting from the original record bearing medium the copy is of iswritten.

Now, the record information recorded on the back surface of a masterrecord bearing medium 71 as the original and an index signal to bedescribed later are reproduced by the data reproducer 73, and memorizedin the D-RAM 74. Then, the record information memorized in this D-RAM 74is recorded by the data recorder 75 on the back surface of another itemof the medium. At this time, the numeral representing the number of copycycles in the ID region having the index signal written therein providedat one end of the first area in which a fixed length data mainly of astill picture was recorded in the recording area of the record bearingmedium 72 is incremented by 1 in the D-RAM 74. Therefore, upon seeingthe information recorded in this index area, which one of the recordbearing media, the given record bearing medium was copied from can beunderstood easily. To this purpose, it is also possible to print adesired still picture from the still picture recording area (2 ofFIG. 1) on the back side of the record bearing medium 72 directlythrough the printer 76, and affix the print to the front surface 72' ofthe record bearing medium 72. Also, the still picture print to beaffixed to the front surface of this record bearing medium may beobtained by copying the still picture print affixed to the front surface71' of the original record bearing medium with the copier or the like.

According to the system of the structure described above, it has afunction of being able to copy from one record bearing medium to anotherrecord bearing medium, and a record bearing medium capable ofdetermining what a number of generations counting from the originalrecord bearing medium this record bearing medium is a copy of can beobtained.

FIG. 13 is a diagram roughly illustrating the structure of a controlsystem using such a record bearing medium as described above. 201 is arecording and reproduction apparatus to be described later; 202 is acontroller; 203 is a video controller; 204 is an audio amplifier; 205 isa control system for others; 206 is a video monitor device such asmonitor TV, projector, etc.; 207 is a speaker; 208 is a card as large asthe size of a portable credit card of about 55 mm×85 mm; 209 is a squaredisc of about 50-85 mm in side length.

In the apparatus of FIG. 13, a system is so constructed that uponinsertion of the card 208 or the disc 209 into the recording andreproduction apparatus 201, a video signal output, an audio signaloutput and data such as controls are supplied respectively to the videocontroller 203, the audio amplifier 204 and the controller 202. Theabove-mentioned three kinds of information each are output from thevideo monitor (monitor TV, projector) 206, the speaker 207 and thecontrol system 205.

Here, the controller 202 sends a FADE signal to the video controller203, thereby it being made possible to control the luminance of all thearea of the picture frame, too. Also, as to the audio amplifier 204, asimilar measure may be taken so that it becomes possible to adjust thesound volume balance among a plurality of audio channels.

Also, FIGS. 14(a) and 14(b) show the practical structures of the recordbearing media 208 and 209 of FIG. 13, FIG. 14(a) being a figure of thedisc-shaped record bearing medium and FIG. 14(b) being a figure of thecard-shaped record bearing medium. Though an example of a zigzag form ofrecording track pattern is shown in FIG. 14(b), besides this, it is alsopossible to array arcuate track patterns of high data rate.

By the way, as the constituent elements of this system, depending onwhether the record bearing medium 208 or 209 is in the form of the card208 or the disc 209, the arrangement of the neighborhood of thephotoelectric transducer portion for the recording and reproductionbecomes different. Also, there are differences of the data rate, etc. Inthe following, therefore, taking an example of a 3 in. square recordbearing medium or the disc 209, explanation is made concretely.

Before the explanation of the system using the disc 209 as thedisc-shaped record bearing medium, the record bearing medium isexplained in a bit greater detail by using FIG. 14(a).

Recording is carried out, while forming a track pattern of helical shapeor of shape of a plurality of concentric circles in the center of thesquare as viewed from the recording surface side of the disc 209. Asshown in the figure, the recording area of round shape is used individed two parts. One of them is a first recording area which is afixed length area where a fixed volume of information is alwaysrecorded, and is provided on the recording start side. In general, forrotation control of constant linear velocity is performed, it isadvantageous to use an outer peripheral side as far as possible. Hencethe recording start point is set in the outermost periphery. This fixedlength area is a recording area in which the recordable data amountcapable of recording information of at least one still picture isconstant (the number of pictures to be recorded may be changed). Theother is, to be provided contiguous to this fixed length Area, avariable length area generally of more inner peripheral side. Thisvariable length area is able to set a size of the recording areadepending on the amount of information to be recorded. Also, this areais suited to record time dependent information such as a motion pictureand sound. In the case of the motion picture, the amount of informationis too large even at as low a quality as the NTSC. Therefore, for thedigital case, a high efficiency coding circuit becomes necessary. Forthe case of audio signals, the usual PCM coding makes the data amountproper.

Next, using FIG. 15, a concrete arrangement of the main parts of therecording and reproduction apparatus 201 of FIG. 13 is described. InFIG. 15, the disc 209 is set with its recording surface up on a turntable 230. The turn table 220 is driven to rotate by a motor 231. Whenrotation starts, the disc 209 is fixed secured by a stopper 232 on theturn table 230. The turn table 230 is controlled in accordance with theposition of an optical head 233 by a motor servo circuit 234 on thebasis of information of the number of revolutions and information of thephase of rotation produced from a frequency generator (FG) and a pulsegenerator (PG) linked to the motor 231 so that the relative speed of theoptical head 233 and the disc 209 is made constant. Also, the opticalhead 233 moves in a direction indicated by the arrow to reproduce (orrecord) the information successively. The determination of the positionof this optical head 233 is controlled by a head position determiningmechanism 237 comprised of a magnetic movable coil and others.

In such a manner, the relative position of the head 233 is controlledwhen recording or reproducing is carried out by radiating a laser beamto the disc 209.

When in recording, spots of very minute area called bits whosereflectance characteristic is different from the others are formed onthe disc 209 by using the energy of the laser beam. When inreproduction, depending on the reflection characteristic of theirradiated laser beam, a "0" is obtained if there if no change in thecharacteristic, or "1" if change occurs, detection is made in the formof digital signal. And, to differentiate the reflection characteristicthere are methods that holes are bored to generate diffraction, causingthe strength of reflection to lower, that the phase of the mediummaterial is changed to change the strength of reflection, and that theKerr rotation angle is changed by using the magneto-optical effect. Anyof them may be employed.

Also, a pickup portion 238 is provided on the optical head 233 and has,for example, a 4-component photoelectric transducer of PIN photodiodesto detect the information signals. The detected information signals aresent to a signal processing circuit 236, wherein they are converted tonecessary signal forms, and are output therefrom as the video signal,the audio signal and the control signals. Further, in this signalprocessing circuit 236, to form a tracking control signal for the headposition determining mechanism 237, a signal from the pickup portion 238is supplied as the tracking signal to a system controller 235. Thissystem controller 235 controls not only determination of the position ofthe optical head 233 but also the motor servo circuit 234.

FIG. 16 is a perspective view illustrating the details of the stopper232 of FIG. 15. In FIG. 16, arms 242 and 243 movably provided on supportshafts 244 and 245 have disc presser plates 246 and 247 at their oneends, the opposite ends of which have a common weight 241. This weight241 is attracted by a spring (not shown) to a nearer position to thedisc 209. For this reason, the presser plates 246 and 247 are put insuch positions that the disc 209 is freely set on the turn table 230.When the disc 209 is set on the turn table 230 and rotation is started,the weight 241 is moved by the centrifugal force to a directionindicated by arrow in FIG. 16. This causes the arms 242 and 243 to moveso that the presser plates 246 and 247 press and fixedly secure the disc209.

FIGS. 17(a) and 17(b) are block diagrams illustrating the constructionand arrangement of the parts of the signal processing circuit 236 ofFIG. 15, FIG. 17(a) illustrating a signal processing system for therecording and FIG. 17(b) illustrating a signal processing system for thereproduction.

In FIGS. 17(a) and 17(b), a video signal and stereo audio signals areconverted to digital form by A/D converters 250, 251 and 252respectively. The video signal for one frame is stored in a frame memory253, while the audio data as the parallel signals of stereo areconverted to a serial data by a multiplexer circuit 254. In a switch255, depending on the recording area, the data is selected. In an adder257, the selected data is mixed with the output signal from anotherswitch 256. The inputs of the switch 256 are the main data and thesub-data, and are selectively output according to the necessity. Theswitches 255 and 256 are changed over between a terminal "a" side whenrecording on the fixed length area and a terminal "b" side whenrecording on the variable length area.

Incidentally, it is considered that the main data includes MIDI data tobe described later and others, and the sub-data include data for initialsettings, user's code and others.

In FIG. 17(b), the signal recorded on the disc 209 is reproduced by thepickup portion 238, and this reproduced signal is supplied as thetracking signal to the system controller. The reproduced signal is alsodemodulated by the digital modulation circuit 261 and the code error iscorrected by the error correction circuit 262.

The reproduced digital signal which has been corrected in the code erroris distributed by the data allotter 263 to switches 264 and 269connected, respectively, to a terminal side at the time of reproductionof a fixed length area and to terminal "b" side at the time ofreproduction of a variable-length area. By the switch 264, the videosignal and the audio signal are inputted, respectively, to a framememory 253 and an allotter 265. The video signal such as a still imagesignal read out from the frame memory 253 is converted into an analogsignal by a D/A convertor 266 and outputted as the video output.Meanwhile by the allotter 265, the audio signal is separated into left(L) data and right (R) data, both being converted into an analog signalby D/A convertors 267 and 268, respectively, and outputted as the audiooutput.

Further by the switch 269, the main data including MIDI data, etc., isoutputted at the time of reproduction of the fixed-length area and thesub-data including user's code, etc., is outputted through a lineseparate from the main data at the time of reproduction of thevariable-length area.

FIG. 18 is a diagram illustrating the element arrangement of the stillpicture signal recorded in the fixed length area or first recording areaon the disc 209 shown in FIG. 14(a). Y denotes the luminance signal, andR-Y and B-Y each are a color difference signal. Each picture elementconsists of 8 bits.

By setting the sampling frequency so as to obtain the picture elementsshown in FIG. 18, an equivalent image quality to the high-definition TVcan be obtained. If the image quality may be as rough as correspondingto the NTSC system, on the other hand, a sampling frequency equal to 3-4times the color subcarrier frequency fsc is sufficient.

FIG. 19 is a diagram illustrating a data array for 1/5 second in thevariable length area or second recording area on the disc 209 shown inFIG. 14(a), for a case that as an example of the main data, the MIDIsignal as the audio signal is digitized at a sampling frequency of2f_(H) (where f_(H) is the horizontal synchronous frequency.) Itscontent is shown below:

Audio 31.5 k sampling

MIDI 31.25 k bits/sec.

FADE 1 byte per frame

Others 200 bits/sec.

From the above, in the example of FIG. 18, about 5M bytes are assignedto one frame of still picture, and in the example of FIG. 19, about 5Mbytes are used up per minute. Therefore, the initial system design iseasily carried out.

FIG. 20 shows arrangement of a system of the case that the system ofFIG. 13 is applied to a shopwindow display (POP) system. 280 is a cameraas the commodity for display; 281 is an exhibition table which alsoserves as a screen; 282 is a video projector for outputting the videosignal, this video being projected onto the screen 281 on the basis ofthe signal of the video controller 203. 283 is a lamp for illumination,which is controlled in accordance with the before-mentioned other data(C(1) of FIG. 19) by the controller 202. Since this data have 200bits/sec. if the on-off control is 100 msec., up to 20 lamps can becontrolled. The audio signal passes through the audio amplifier 204, andis output as the sound signals by speakers 207-R, 207-L.

The brilliance of the projected still picture by this projector 282 canbe determined in each frame by the FADE data. If the data setting ischanged, a color fade also becomes possible.

FIG. 21 is a block diagram roughly illustrating arrangement of a systemof the case that the system of FIG. 13 is applied to a soundreproduction system, wherein the audio signal and the video signal areoutput in a similar manner to that in the case of FIG. 20. Thischaracteristic feature resides in transmission of the main dataaccording to the MIDI standard.

Incidentally, MIDI is short for Musical Instrument Digital Interface. Tocontrol the electronic musical instruments, the international standardhas been set forth by musical instrument makers in various countries.Recently, however, as personal computers (particularly MSXs) are widelyspreading, it begins to be applied to other purposes than the electronicmusic instruments, thus providing a format of high worth in utility.And, the data rate of this MIDI is 31.25 bits/sec. and the minimum unitis 10 bits. This is because a start bit and an end bit are added to 1byte of data at the head and tail thereof, for transmission is made inunits of 10 bits. In this system, however, the net data of 8 bitssuffice. Therefore, when recording, the two bits, the start and the end,are removed. When reproducing, the start and end bits are added again tosend out the data in the form of the MIDI format. This conversion isperformed by an interface 292, and the result is supplied to an MIDIadopted electronic musical instrument for producing music (the form maybe that of the mere audio system). And, the audio signal produced fromthis MIDI adopted electronic musical instrument 293 in mixture with thebefore-mentioned audio signal is amplified by the audio amplifier 204,and output from the speaker 207. Also, if the other data (C(1) of FIG.19) supplied to the controller 202 is used as the code data, musicalscores, lyrics, etc. can be transmitted, so, with the controller 202connected to a printer 291, lyrics cards 294 can be printed out. If thecharacter data are supplied in superimposed relation to the videocontroller 203, the still picture and the lyrics can be viewed insuperimposed relation on the monitor 290.

By the way, on connection of the audio amplifier 204 further to amicrophone (not shown), a system can be set up to help sing a song whilelooking at the lyrics and hearing the background music.

What is claimed is:
 1. A reproducing apparatus for reproducing aninformation signal from a recording medium in which a recording mediumhaving a modulated information signal recorded thereon by one ofdifferent recording systems, comprising:(a) irradiating means forirradiating said recording medium with a light beam; (b) photoelectricdetecting means for receiving light beam reflexed from said recordingmedium and for generating an electric signal as the modulatedinformation signal in response to the received light beam, saidphotoelectric detecting means being arranged to generate said electricsignal by different processes in the case where the modulatedinformation signal is recorded on said recording medium by a firstsystem and in the case where the modulated information signal isrecorded on the recording medium by a second system different from saidfirst system; and (c) converting means for converting said informationsignal from said electric signal, said converting means including ademodulation circuit which is commonly utilized for demodulating both ofthe modulated information signal s recorded by first and second systems.2. An apparatus according to claim 1, wherein said photoelectricdetecting means is arranged to detect a rotation of a polarization planefrom said reflected light beam in the case where the information signalis recorded on said recording medium by said first system and to detecta reflectivity in the case where the information signal is recorded onthe recording medium by said second system.
 3. An apparatus according toclaim 2, wherein said first system is a recording system utilizing amagneto-optical effect and said photoelectric detecting means isarranged to detect the rotation angle of the reflected light beam byKerr Effect in the case where the information signal is recorded on saidrecording medium by said first system.
 4. An apparatus according toclaim 2, wherein said second system is a system in which the recordingmedium has a surface, the surface has a hole formed therein to generatea diffraction of the light beam and the recording is effected bychanging the reflectivity of the light beam.
 5. An apparatus accordingto claim 2, wherein said second system is a system in which therecording medium consists of a plurality of layers and the recording iseffected by generating a change of each layer to change the reflectivityof the light beam.